Convert to maildir?

I get this when running cpanel updates. What is the difference between mbox and maildir? All i need to do is run /scripts/convert2maildir ? no one is havent any issues with it?
Thanks.

@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@
@! ATTENTION! mbox is deprecated in this release !@
@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@
@ You should switch to using maildir as soon as @
@ possible. To switch run @
@ /scripts/convert2maildir @
@ in a root shell. @
@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@